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Author Topic: Fiberglass vs. MLV in my window  (Read 6250 times)


  • Guest
Fiberglass vs. MLV in my window
« on: April 04, 2009, 07:34:47 PM »


I have a question about soundproofing the 3" deep, 3' x 5' window in my 3rd floor apartment bedroom. Currently I have it plugged up with R-19 fiberglass insulation backed with a piece of hardboard. It got rid of the noise I was trying to eliminate, a dull drone I never actually found the source of. It sounded like wind or water blowing through a pipe, and it was constant, even at night. I live near an interstate and a busy street so I eventually decided it was the sound of the wind carrying distant traffic noise. I can still hear nearby cars go by faintly, but I can deal much better with that intermittent noise than the constant noise.

Anyway, I notice whenever I'm in my bedroom my throat feels scratchy and I am wondering how I may be reacting to this fiberglass. I know it's supposed to be safe, but I'm still having second thoughts, and I am pretty inclined to try something else. My main question is how the 2" mass-loaded vinyl mat sold here would compare to what I have currently. Would it block more sound? Less sound? What if I got a 2" mat + a 1" mat to fill the whole 3 inches of depth? Would buying a solid mat vs. strips of linear feet be better? I figure I am going to have to cut it either way to accommodate the 3' width. I would really appreciate any information in this regard! Thank you.

Randy S

  • Guest
Re: Fiberglass vs. MLV in my window
« Reply #1 on: April 06, 2009, 03:57:47 PM »

Here is a far better solution for your window.

Use 2" SSP Foam Mat.


  • Guest
Re: Fiberglass vs. MLV in my window
« Reply #2 on: April 09, 2009, 07:53:54 PM »

Hop on the web and see if you can find somebody selling a remnant piece of plexiglass, at least 3/8" thick.  Forget about insulation between the glass and the plug - if you get a second pane with a lot of mass, that will block the noise adequately and you get to keep your view/light.


  • Guest
Re: Fiberglass vs. MLV in my window
« Reply #3 on: May 11, 2009, 06:21:25 AM »